drivers/gpu/drm/vmwgfx/ttm_object.c

   1 /* SPDX-License-Identifier: GPL-2.0 OR MIT */
   2 /**************************************************************************
   3  *
   4  * Copyright (c) 2009-2013 VMware, Inc., Palo Alto, CA., USA
   5  * All Rights Reserved.
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a
   8  * copy of this software and associated documentation files (the
   9  * "Software"), to deal in the Software without restriction, including
  10  * without limitation the rights to use, copy, modify, merge, publish,
  11  * distribute, sub license, and/or sell copies of the Software, and to
  12  * permit persons to whom the Software is furnished to do so, subject to
  13  * the following conditions:
  14  *
  15  * The above copyright notice and this permission notice (including the
  16  * next paragraph) shall be included in all copies or substantial portions
  17  * of the Software.
  18  *
  19  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  20  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  21  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
  22  * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
  23  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
  24  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
  25  * USE OR OTHER DEALINGS IN THE SOFTWARE.
  26  *
  27  **************************************************************************/
  28 /*
  29  * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
  30  *
  31  * While no substantial code is shared, the prime code is inspired by
  32  * drm_prime.c, with
  33  * Authors:
  34  *      Dave Airlie <airlied@redhat.com>
  35  *      Rob Clark <rob.clark@linaro.org>
  36  */
  37 /** @file ttm_ref_object.c
  38  *
  39  * Base- and reference object implementation for the various
  40  * ttm objects. Implements reference counting, minimal security checks
  41  * and release on file close.
  42  */
  43
  44
  45 /**
  46  * struct ttm_object_file
  47  *
  48  * @tdev: Pointer to the ttm_object_device.
  49  *
  50  * @lock: Lock that protects the ref_list list and the
  51  * ref_hash hash tables.
  52  *
  53  * @ref_list: List of ttm_ref_objects to be destroyed at
  54  * file release.
  55  *
  56  * @ref_hash: Hash tables of ref objects, one per ttm_ref_type,
  57  * for fast lookup of ref objects given a base object.
  58  */
  59
  60 #define pr_fmt(fmt) "[TTM] " fmt
  61
  62 #include <linux/list.h>
  63 #include <linux/spinlock.h>
  64 #include <linux/slab.h>
  65 #include <linux/atomic.h>
  66 #include "ttm_object.h"
  67
  68 struct ttm_object_file {
  69         struct ttm_object_device *tdev;
  70         spinlock_t lock;
  71         struct list_head ref_list;
  72         struct drm_open_hash ref_hash[TTM_REF_NUM];
  73         struct kref refcount;
  74 };
  75
  76 /**
  77  * struct ttm_object_device
  78  *
  79  * @object_lock: lock that protects the object_hash hash table.
  80  *
  81  * @object_hash: hash table for fast lookup of object global names.
  82  *
  83  * @object_count: Per device object count.
  84  *
  85  * This is the per-device data structure needed for ttm object management.
  86  */
  87
  88 struct ttm_object_device {
  89         spinlock_t object_lock;
  90         struct drm_open_hash object_hash;
  91         atomic_t object_count;
  92         struct ttm_mem_global *mem_glob;
  93         struct dma_buf_ops ops;
  94         void (*dmabuf_release)(struct dma_buf *dma_buf);
  95         size_t dma_buf_size;
  96         struct idr idr;
  97 };
  98
  99 /**
 100  * struct ttm_ref_object
 101  *
 102  * @hash: Hash entry for the per-file object reference hash.
 103  *
 104  * @head: List entry for the per-file list of ref-objects.
 105  *
 106  * @kref: Ref count.
 107  *
 108  * @obj: Base object this ref object is referencing.
 109  *
 110  * @ref_type: Type of ref object.
 111  *
 112  * This is similar to an idr object, but it also has a hash table entry
 113  * that allows lookup with a pointer to the referenced object as a key. In
 114  * that way, one can easily detect whether a base object is referenced by
 115  * a particular ttm_object_file. It also carries a ref count to avoid creating
 116  * multiple ref objects if a ttm_object_file references the same base
 117  * object more than once.
 118  */
 119
 120 struct ttm_ref_object {
 121         struct rcu_head rcu_head;
 122         struct drm_hash_item hash;
 123         struct list_head head;
 124         struct kref kref;
 125         enum ttm_ref_type ref_type;
 126         struct ttm_base_object *obj;
 127         struct ttm_object_file *tfile;
 128 };
 129
 130 static void ttm_prime_dmabuf_release(struct dma_buf *dma_buf);
 131
 132 static inline struct ttm_object_file *
 133 ttm_object_file_ref(struct ttm_object_file *tfile)
 134 {
 135         kref_get(&tfile->refcount);
 136         return tfile;
 137 }
 138
 139 static void ttm_object_file_destroy(struct kref *kref)
 140 {
 141         struct ttm_object_file *tfile =
 142                 container_of(kref, struct ttm_object_file, refcount);
 143
 144         kfree(tfile);
 145 }
 146
 147
 148 static inline void ttm_object_file_unref(struct ttm_object_file **p_tfile)
 149 {
 150         struct ttm_object_file *tfile = *p_tfile;
 151
 152         *p_tfile = NULL;
 153         kref_put(&tfile->refcount, ttm_object_file_destroy);
 154 }
 155
 156
 157 int ttm_base_object_init(struct ttm_object_file *tfile,
 158                          struct ttm_base_object *base,
 159                          bool shareable,
 160                          enum ttm_object_type object_type,
 161                          void (*refcount_release) (struct ttm_base_object **),
 162                          void (*ref_obj_release) (struct ttm_base_object *,
 163                                                   enum ttm_ref_type ref_type))
 164 {
 165         struct ttm_object_device *tdev = tfile->tdev;
 166         int ret;
 167
 168         base->shareable = shareable;
 169         base->tfile = ttm_object_file_ref(tfile);
 170         base->refcount_release = refcount_release;
 171         base->ref_obj_release = ref_obj_release;
 172         base->object_type = object_type;
 173         kref_init(&base->refcount);
 174         idr_preload(GFP_KERNEL);
 175         spin_lock(&tdev->object_lock);
 176         ret = idr_alloc(&tdev->idr, base, 1, 0, GFP_NOWAIT);
 177         spin_unlock(&tdev->object_lock);
 178         idr_preload_end();
 179         if (ret < 0)
 180                 return ret;
 181
 182         base->handle = ret;
 183         ret = ttm_ref_object_add(tfile, base, TTM_REF_USAGE, NULL, false);
 184         if (unlikely(ret != 0))
 185                 goto out_err1;
 186
 187         ttm_base_object_unref(&base);
 188
 189         return 0;
 190 out_err1:
 191         spin_lock(&tdev->object_lock);
 192         idr_remove(&tdev->idr, base->handle);
 193         spin_unlock(&tdev->object_lock);
 194         return ret;
 195 }
 196
 197 static void ttm_release_base(struct kref *kref)
 198 {
 199         struct ttm_base_object *base =
 200             container_of(kref, struct ttm_base_object, refcount);
 201         struct ttm_object_device *tdev = base->tfile->tdev;
 202
 203         spin_lock(&tdev->object_lock);
 204         idr_remove(&tdev->idr, base->handle);
 205         spin_unlock(&tdev->object_lock);
 206
 207         /*
 208          * Note: We don't use synchronize_rcu() here because it's far
 209          * too slow. It's up to the user to free the object using
 210          * call_rcu() or ttm_base_object_kfree().
 211          */
 212
 213         ttm_object_file_unref(&base->tfile);
 214         if (base->refcount_release)
 215                 base->refcount_release(&base);
 216 }
 217
 218 void ttm_base_object_unref(struct ttm_base_object **p_base)
 219 {
 220         struct ttm_base_object *base = *p_base;
 221
 222         *p_base = NULL;
 223
 224         kref_put(&base->refcount, ttm_release_base);
 225 }
 226
 227 /**
 228  * ttm_base_object_noref_lookup - look up a base object without reference
 229  * @tfile: The struct ttm_object_file the object is registered with.
 230  * @key: The object handle.
 231  *
 232  * This function looks up a ttm base object and returns a pointer to it
 233  * without refcounting the pointer. The returned pointer is only valid
 234  * until ttm_base_object_noref_release() is called, and the object
 235  * pointed to by the returned pointer may be doomed. Any persistent usage
 236  * of the object requires a refcount to be taken using kref_get_unless_zero().
 237  * Iff this function returns successfully it needs to be paired with
 238  * ttm_base_object_noref_release() and no sleeping- or scheduling functions
 239  * may be called inbetween these function callse.
 240  *
 241  * Return: A pointer to the object if successful or NULL otherwise.
 242  */
 243 struct ttm_base_object *
 244 ttm_base_object_noref_lookup(struct ttm_object_file *tfile, uint32_t key)
 245 {
 246         struct drm_hash_item *hash;
 247         struct drm_open_hash *ht = &tfile->ref_hash[TTM_REF_USAGE];
 248         int ret;
 249
 250         rcu_read_lock();
 251         ret = drm_ht_find_item_rcu(ht, key, &hash);
 252         if (ret) {
 253                 rcu_read_unlock();
 254                 return NULL;
 255         }
 256
 257         __release(RCU);
 258         return drm_hash_entry(hash, struct ttm_ref_object, hash)->obj;
 259 }
 260 EXPORT_SYMBOL(ttm_base_object_noref_lookup);
 261
 262 struct ttm_base_object *ttm_base_object_lookup(struct ttm_object_file *tfile,
 263                                                uint32_t key)
 264 {
 265         struct ttm_base_object *base = NULL;
 266         struct drm_hash_item *hash;
 267         struct drm_open_hash *ht = &tfile->ref_hash[TTM_REF_USAGE];
 268         int ret;
 269
 270         rcu_read_lock();
 271         ret = drm_ht_find_item_rcu(ht, key, &hash);
 272
 273         if (likely(ret == 0)) {
 274                 base = drm_hash_entry(hash, struct ttm_ref_object, hash)->obj;
 275                 if (!kref_get_unless_zero(&base->refcount))
 276                         base = NULL;
 277         }
 278         rcu_read_unlock();
 279
 280         return base;
 281 }
 282
 283 struct ttm_base_object *
 284 ttm_base_object_lookup_for_ref(struct ttm_object_device *tdev, uint32_t key)
 285 {
 286         struct ttm_base_object *base;
 287
 288         rcu_read_lock();
 289         base = idr_find(&tdev->idr, key);
 290
 291         if (base && !kref_get_unless_zero(&base->refcount))
 292                 base = NULL;
 293         rcu_read_unlock();
 294
 295         return base;
 296 }
 297
 298 /**
 299  * ttm_ref_object_exists - Check whether a caller has a valid ref object
 300  * (has opened) a base object.
 301  *
 302  * @tfile: Pointer to a struct ttm_object_file identifying the caller.
 303  * @base: Pointer to a struct base object.
 304  *
 305  * Checks wether the caller identified by @tfile has put a valid USAGE
 306  * reference object on the base object identified by @base.
 307  */
 308 bool ttm_ref_object_exists(struct ttm_object_file *tfile,
 309                            struct ttm_base_object *base)
 310 {
 311         struct drm_open_hash *ht = &tfile->ref_hash[TTM_REF_USAGE];
 312         struct drm_hash_item *hash;
 313         struct ttm_ref_object *ref;
 314
 315         rcu_read_lock();
 316         if (unlikely(drm_ht_find_item_rcu(ht, base->handle, &hash) != 0))
 317                 goto out_false;
 318
 319         /*
 320          * Verify that the ref object is really pointing to our base object.
 321          * Our base object could actually be dead, and the ref object pointing
 322          * to another base object with the same handle.
 323          */
 324         ref = drm_hash_entry(hash, struct ttm_ref_object, hash);
 325         if (unlikely(base != ref->obj))
 326                 goto out_false;
 327
 328         /*
 329          * Verify that the ref->obj pointer was actually valid!
 330          */
 331         rmb();
 332         if (unlikely(kref_read(&ref->kref) == 0))
 333                 goto out_false;
 334
 335         rcu_read_unlock();
 336         return true;
 337
 338  out_false:
 339         rcu_read_unlock();
 340         return false;
 341 }
 342
 343 int ttm_ref_object_add(struct ttm_object_file *tfile,
 344                        struct ttm_base_object *base,
 345                        enum ttm_ref_type ref_type, bool *existed,
 346                        bool require_existed)
 347 {
 348         struct drm_open_hash *ht = &tfile->ref_hash[ref_type];
 349         struct ttm_ref_object *ref;
 350         struct drm_hash_item *hash;
 351         struct ttm_mem_global *mem_glob = tfile->tdev->mem_glob;
 352         struct ttm_operation_ctx ctx = {
 353                 .interruptible = false,
 354                 .no_wait_gpu = false
 355         };
 356         int ret = -EINVAL;
 357
 358         if (base->tfile != tfile && !base->shareable)
 359                 return -EPERM;
 360
 361         if (existed != NULL)
 362                 *existed = true;
 363
 364         while (ret == -EINVAL) {
 365                 rcu_read_lock();
 366                 ret = drm_ht_find_item_rcu(ht, base->handle, &hash);
 367
 368                 if (ret == 0) {
 369                         ref = drm_hash_entry(hash, struct ttm_ref_object, hash);
 370                         if (kref_get_unless_zero(&ref->kref)) {
 371                                 rcu_read_unlock();
 372                                 break;
 373                         }
 374                 }
 375
 376                 rcu_read_unlock();
 377                 if (require_existed)
 378                         return -EPERM;
 379
 380                 ret = ttm_mem_global_alloc(mem_glob, sizeof(*ref),
 381                                            &ctx);
 382                 if (unlikely(ret != 0))
 383                         return ret;
 384                 ref = kmalloc(sizeof(*ref), GFP_KERNEL);
 385                 if (unlikely(ref == NULL)) {
 386                         ttm_mem_global_free(mem_glob, sizeof(*ref));
 387                         return -ENOMEM;
 388                 }
 389
 390                 ref->hash.key = base->handle;
 391                 ref->obj = base;
 392                 ref->tfile = tfile;
 393                 ref->ref_type = ref_type;
 394                 kref_init(&ref->kref);
 395
 396                 spin_lock(&tfile->lock);
 397                 ret = drm_ht_insert_item_rcu(ht, &ref->hash);
 398
 399                 if (likely(ret == 0)) {
 400                         list_add_tail(&ref->head, &tfile->ref_list);
 401                         kref_get(&base->refcount);
 402                         spin_unlock(&tfile->lock);
 403                         if (existed != NULL)
 404                                 *existed = false;
 405                         break;
 406                 }
 407
 408                 spin_unlock(&tfile->lock);
 409                 BUG_ON(ret != -EINVAL);
 410
 411                 ttm_mem_global_free(mem_glob, sizeof(*ref));
 412                 kfree(ref);
 413         }
 414
 415         return ret;
 416 }
 417
 418 static void __releases(tfile->lock) __acquires(tfile->lock)
 419 ttm_ref_object_release(struct kref *kref)
 420 {
 421         struct ttm_ref_object *ref =
 422             container_of(kref, struct ttm_ref_object, kref);
 423         struct ttm_base_object *base = ref->obj;
 424         struct ttm_object_file *tfile = ref->tfile;
 425         struct drm_open_hash *ht;
 426         struct ttm_mem_global *mem_glob = tfile->tdev->mem_glob;
 427
 428         ht = &tfile->ref_hash[ref->ref_type];
 429         (void)drm_ht_remove_item_rcu(ht, &ref->hash);
 430         list_del(&ref->head);
 431         spin_unlock(&tfile->lock);
 432
 433         if (ref->ref_type != TTM_REF_USAGE && base->ref_obj_release)
 434                 base->ref_obj_release(base, ref->ref_type);
 435
 436         ttm_base_object_unref(&ref->obj);
 437         ttm_mem_global_free(mem_glob, sizeof(*ref));
 438         kfree_rcu(ref, rcu_head);
 439         spin_lock(&tfile->lock);
 440 }
 441
 442 int ttm_ref_object_base_unref(struct ttm_object_file *tfile,
 443                               unsigned long key, enum ttm_ref_type ref_type)
 444 {
 445         struct drm_open_hash *ht = &tfile->ref_hash[ref_type];
 446         struct ttm_ref_object *ref;
 447         struct drm_hash_item *hash;
 448         int ret;
 449
 450         spin_lock(&tfile->lock);
 451         ret = drm_ht_find_item(ht, key, &hash);
 452         if (unlikely(ret != 0)) {
 453                 spin_unlock(&tfile->lock);
 454                 return -EINVAL;
 455         }
 456         ref = drm_hash_entry(hash, struct ttm_ref_object, hash);
 457         kref_put(&ref->kref, ttm_ref_object_release);
 458         spin_unlock(&tfile->lock);
 459         return 0;
 460 }
 461
 462 void ttm_object_file_release(struct ttm_object_file **p_tfile)
 463 {
 464         struct ttm_ref_object *ref;
 465         struct list_head *list;
 466         unsigned int i;
 467         struct ttm_object_file *tfile = *p_tfile;
 468
 469         *p_tfile = NULL;
 470         spin_lock(&tfile->lock);
 471
 472         /*
 473          * Since we release the lock within the loop, we have to
 474          * restart it from the beginning each time.
 475          */
 476
 477         while (!list_empty(&tfile->ref_list)) {
 478                 list = tfile->ref_list.next;
 479                 ref = list_entry(list, struct ttm_ref_object, head);
 480                 ttm_ref_object_release(&ref->kref);
 481         }
 482
 483         spin_unlock(&tfile->lock);
 484         for (i = 0; i < TTM_REF_NUM; ++i)
 485                 drm_ht_remove(&tfile->ref_hash[i]);
 486
 487         ttm_object_file_unref(&tfile);
 488 }
 489
 490 struct ttm_object_file *ttm_object_file_init(struct ttm_object_device *tdev,
 491                                              unsigned int hash_order)
 492 {
 493         struct ttm_object_file *tfile = kmalloc(sizeof(*tfile), GFP_KERNEL);
 494         unsigned int i;
 495         unsigned int j = 0;
 496         int ret;
 497
 498         if (unlikely(tfile == NULL))
 499                 return NULL;
 500
 501         spin_lock_init(&tfile->lock);
 502         tfile->tdev = tdev;
 503         kref_init(&tfile->refcount);
 504         INIT_LIST_HEAD(&tfile->ref_list);
 505
 506         for (i = 0; i < TTM_REF_NUM; ++i) {
 507                 ret = drm_ht_create(&tfile->ref_hash[i], hash_order);
 508                 if (ret) {
 509                         j = i;
 510                         goto out_err;
 511                 }
 512         }
 513
 514         return tfile;
 515 out_err:
 516         for (i = 0; i < j; ++i)
 517                 drm_ht_remove(&tfile->ref_hash[i]);
 518
 519         kfree(tfile);
 520
 521         return NULL;
 522 }
 523
 524 struct ttm_object_device *
 525 ttm_object_device_init(struct ttm_mem_global *mem_glob,
 526                        unsigned int hash_order,
 527                        const struct dma_buf_ops *ops)
 528 {
 529         struct ttm_object_device *tdev = kmalloc(sizeof(*tdev), GFP_KERNEL);
 530         int ret;
 531
 532         if (unlikely(tdev == NULL))
 533                 return NULL;
 534
 535         tdev->mem_glob = mem_glob;
 536         spin_lock_init(&tdev->object_lock);
 537         atomic_set(&tdev->object_count, 0);
 538         ret = drm_ht_create(&tdev->object_hash, hash_order);
 539         if (ret != 0)
 540                 goto out_no_object_hash;
 541
 542         idr_init(&tdev->idr);
 543         tdev->ops = *ops;
 544         tdev->dmabuf_release = tdev->ops.release;
 545         tdev->ops.release = ttm_prime_dmabuf_release;
 546         tdev->dma_buf_size = ttm_round_pot(sizeof(struct dma_buf)) +
 547                 ttm_round_pot(sizeof(struct file));
 548         return tdev;
 549
 550 out_no_object_hash:
 551         kfree(tdev);
 552         return NULL;
 553 }
 554
 555 void ttm_object_device_release(struct ttm_object_device **p_tdev)
 556 {
 557         struct ttm_object_device *tdev = *p_tdev;
 558
 559         *p_tdev = NULL;
 560
 561         WARN_ON_ONCE(!idr_is_empty(&tdev->idr));
 562         idr_destroy(&tdev->idr);
 563         drm_ht_remove(&tdev->object_hash);
 564
 565         kfree(tdev);
 566 }
 567
 568 /**
 569  * get_dma_buf_unless_doomed - get a dma_buf reference if possible.
 570  *
 571  * @dma_buf: Non-refcounted pointer to a struct dma-buf.
 572  *
 573  * Obtain a file reference from a lookup structure that doesn't refcount
 574  * the file, but synchronizes with its release method to make sure it has
 575  * not been freed yet. See for example kref_get_unless_zero documentation.
 576  * Returns true if refcounting succeeds, false otherwise.
 577  *
 578  * Nobody really wants this as a public API yet, so let it mature here
 579  * for some time...
 580  */
 581 static bool __must_check get_dma_buf_unless_doomed(struct dma_buf *dmabuf)
 582 {
 583         return atomic_long_inc_not_zero(&dmabuf->file->f_count) != 0L;
 584 }
 585
 586 /**
 587  * ttm_prime_refcount_release - refcount release method for a prime object.
 588  *
 589  * @p_base: Pointer to ttm_base_object pointer.
 590  *
 591  * This is a wrapper that calls the refcount_release founction of the
 592  * underlying object. At the same time it cleans up the prime object.
 593  * This function is called when all references to the base object we
 594  * derive from are gone.
 595  */
 596 static void ttm_prime_refcount_release(struct ttm_base_object **p_base)
 597 {
 598         struct ttm_base_object *base = *p_base;
 599         struct ttm_prime_object *prime;
 600
 601         *p_base = NULL;
 602         prime = container_of(base, struct ttm_prime_object, base);
 603         BUG_ON(prime->dma_buf != NULL);
 604         mutex_destroy(&prime->mutex);
 605         if (prime->refcount_release)
 606                 prime->refcount_release(&base);
 607 }
 608
 609 /**
 610  * ttm_prime_dmabuf_release - Release method for the dma-bufs we export
 611  *
 612  * @dma_buf:
 613  *
 614  * This function first calls the dma_buf release method the driver
 615  * provides. Then it cleans up our dma_buf pointer used for lookup,
 616  * and finally releases the reference the dma_buf has on our base
 617  * object.
 618  */
 619 static void ttm_prime_dmabuf_release(struct dma_buf *dma_buf)
 620 {
 621         struct ttm_prime_object *prime =
 622                 (struct ttm_prime_object *) dma_buf->priv;
 623         struct ttm_base_object *base = &prime->base;
 624         struct ttm_object_device *tdev = base->tfile->tdev;
 625
 626         if (tdev->dmabuf_release)
 627                 tdev->dmabuf_release(dma_buf);
 628         mutex_lock(&prime->mutex);
 629         if (prime->dma_buf == dma_buf)
 630                 prime->dma_buf = NULL;
 631         mutex_unlock(&prime->mutex);
 632         ttm_mem_global_free(tdev->mem_glob, tdev->dma_buf_size);
 633         ttm_base_object_unref(&base);
 634 }
 635
 636 /**
 637  * ttm_prime_fd_to_handle - Get a base object handle from a prime fd
 638  *
 639  * @tfile: A struct ttm_object_file identifying the caller.
 640  * @fd: The prime / dmabuf fd.
 641  * @handle: The returned handle.
 642  *
 643  * This function returns a handle to an object that previously exported
 644  * a dma-buf. Note that we don't handle imports yet, because we simply
 645  * have no consumers of that implementation.
 646  */
 647 int ttm_prime_fd_to_handle(struct ttm_object_file *tfile,
 648                            int fd, u32 *handle)
 649 {
 650         struct ttm_object_device *tdev = tfile->tdev;
 651         struct dma_buf *dma_buf;
 652         struct ttm_prime_object *prime;
 653         struct ttm_base_object *base;
 654         int ret;
 655
 656         dma_buf = dma_buf_get(fd);
 657         if (IS_ERR(dma_buf))
 658                 return PTR_ERR(dma_buf);
 659
 660         if (dma_buf->ops != &tdev->ops)
 661                 return -ENOSYS;
 662
 663         prime = (struct ttm_prime_object *) dma_buf->priv;
 664         base = &prime->base;
 665         *handle = base->handle;
 666         ret = ttm_ref_object_add(tfile, base, TTM_REF_USAGE, NULL, false);
 667
 668         dma_buf_put(dma_buf);
 669
 670         return ret;
 671 }
 672
 673 /**
 674  * ttm_prime_handle_to_fd - Return a dma_buf fd from a ttm prime object
 675  *
 676  * @tfile: Struct ttm_object_file identifying the caller.
 677  * @handle: Handle to the object we're exporting from.
 678  * @flags: flags for dma-buf creation. We just pass them on.
 679  * @prime_fd: The returned file descriptor.
 680  *
 681  */
 682 int ttm_prime_handle_to_fd(struct ttm_object_file *tfile,
 683                            uint32_t handle, uint32_t flags,
 684                            int *prime_fd)
 685 {
 686         struct ttm_object_device *tdev = tfile->tdev;
 687         struct ttm_base_object *base;
 688         struct dma_buf *dma_buf;
 689         struct ttm_prime_object *prime;
 690         int ret;
 691
 692         base = ttm_base_object_lookup(tfile, handle);
 693         if (unlikely(base == NULL ||
 694                      base->object_type != ttm_prime_type)) {
 695                 ret = -ENOENT;
 696                 goto out_unref;
 697         }
 698
 699         prime = container_of(base, struct ttm_prime_object, base);
 700         if (unlikely(!base->shareable)) {
 701                 ret = -EPERM;
 702                 goto out_unref;
 703         }
 704
 705         ret = mutex_lock_interruptible(&prime->mutex);
 706         if (unlikely(ret != 0)) {
 707                 ret = -ERESTARTSYS;
 708                 goto out_unref;
 709         }
 710
 711         dma_buf = prime->dma_buf;
 712         if (!dma_buf || !get_dma_buf_unless_doomed(dma_buf)) {
 713                 DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
 714                 struct ttm_operation_ctx ctx = {
 715                         .interruptible = true,
 716                         .no_wait_gpu = false
 717                 };
 718                 exp_info.ops = &tdev->ops;
 719                 exp_info.size = prime->size;
 720                 exp_info.flags = flags;
 721                 exp_info.priv = prime;
 722
 723                 /*
 724                  * Need to create a new dma_buf, with memory accounting.
 725                  */
 726                 ret = ttm_mem_global_alloc(tdev->mem_glob, tdev->dma_buf_size,
 727                                            &ctx);
 728                 if (unlikely(ret != 0)) {
 729                         mutex_unlock(&prime->mutex);
 730                         goto out_unref;
 731                 }
 732
 733                 dma_buf = dma_buf_export(&exp_info);
 734                 if (IS_ERR(dma_buf)) {
 735                         ret = PTR_ERR(dma_buf);
 736                         ttm_mem_global_free(tdev->mem_glob,
 737                                             tdev->dma_buf_size);
 738                         mutex_unlock(&prime->mutex);
 739                         goto out_unref;
 740                 }
 741
 742                 /*
 743                  * dma_buf has taken the base object reference
 744                  */
 745                 base = NULL;
 746                 prime->dma_buf = dma_buf;
 747         }
 748         mutex_unlock(&prime->mutex);
 749
 750         ret = dma_buf_fd(dma_buf, flags);
 751         if (ret >= 0) {
 752                 *prime_fd = ret;
 753                 ret = 0;
 754         } else
 755                 dma_buf_put(dma_buf);
 756
 757 out_unref:
 758         if (base)
 759                 ttm_base_object_unref(&base);
 760         return ret;
 761 }
 762
 763 /**
 764  * ttm_prime_object_init - Initialize a ttm_prime_object
 765  *
 766  * @tfile: struct ttm_object_file identifying the caller
 767  * @size: The size of the dma_bufs we export.
 768  * @prime: The object to be initialized.
 769  * @shareable: See ttm_base_object_init
 770  * @type: See ttm_base_object_init
 771  * @refcount_release: See ttm_base_object_init
 772  * @ref_obj_release: See ttm_base_object_init
 773  *
 774  * Initializes an object which is compatible with the drm_prime model
 775  * for data sharing between processes and devices.
 776  */
 777 int ttm_prime_object_init(struct ttm_object_file *tfile, size_t size,
 778                           struct ttm_prime_object *prime, bool shareable,
 779                           enum ttm_object_type type,
 780                           void (*refcount_release) (struct ttm_base_object **),
 781                           void (*ref_obj_release) (struct ttm_base_object *,
 782                                                    enum ttm_ref_type ref_type))
 783 {
 784         mutex_init(&prime->mutex);
 785         prime->size = PAGE_ALIGN(size);
 786         prime->real_type = type;
 787         prime->dma_buf = NULL;
 788         prime->refcount_release = refcount_release;
 789         return ttm_base_object_init(tfile, &prime->base, shareable,
 790                                     ttm_prime_type,
 791                                     ttm_prime_refcount_release,
 792                                     ref_obj_release);
 793 }